The invention relates to colorimetric indicators, and more particularly to colorimetric indicators for use in medical devices.
Invasive and non-invasive monitoring devices, such as, but not limited to, monitoring electrodes, are commonly used for medical applications. Such monitoring devices may or may not be reusable. For example, electrocardiograph (EEG) and electroencephalography (EEG) lead-sets may be reusable, disposable, or single patient single use devices. Reusable medical devices need to be cleaned after every patient use and also possibly during one patient stay with a defined time period.
In healthcare applications, to reduce or prevent infectious contamination, it is often desirable to provide indicators for devices, where the indicators are configured to provide signals representative of a time period for which a medical device has been in use. For example, it may be desirable to use indicators to indicate a useful life, a sanitization state, a contamination level, or an infection state of the devices. In case of multiple users, the monitoring electrodes and lead-sets may need to be cleansed after use by one patient and before use by another patient to prevent transfer of infections from one patient to another. Whereas, in case of single user, the monitoring electrodes and lead-sets may need to be cleansed and sterilized at regular intervals while being used by the same patient.
Typically, reusable and single patient use medical devices, such as, but not limited to, electrodes and lead-sets, may further cumulative infectious contamination due to the continuous contact of the device with the patient skin, body secretions, and inaccurate cleansing and disinfection. Usually, in case of single patient use devices, this infectious contamination is minimized by disposing the device after the device has been used for a determined period of time. However, existing medical devices do not provide information regarding the time period for which a particular device has been in use. The lack of information or indication regarding the use time of the medical device impairs the effect of the single patient use devices in controlling infection.
Typically, a use time of the medical device or accessory is controlled manually. Currently, a user or operator of the medical device needs to rely on instructions, warnings and cautions in user manuals, or labels on the medical device that suggest a suitable use time for that device. However, the information in the user manual regarding the use time of the device still does not provide information regarding the use time of the device. That is, the manuals do not provide information as to for how long the medical device has been in use. Further, reading the instructions regarding the use time and following the instructions are dependent on the operator, attendant or physician tending to the patient. Moreover, currently, it is not self-evident if the medical device has been in use previously or is new. For example, in case of ECG electrodes, it is difficult to determine whether the accessory is used or unused, or an amount of time for which the accessory has been in use. Lack of such indicators or information may adversely affect the use of medical devices for infection control.